Evolutionary Origins of Multicellularity

The evolution of multicellularity was a major evolutionary transition that led to the emergence of a new level of biological complexity. At least two dozen such transitions have taken place in diverse groups, leading in some cases to evolutionary radiations with major consequences for biodiversity. Like other major evolutionary transitions, multicellularity increases biological complexity through the formation of new organizational structures. For example, component cells of multicellular individuals forego opportunities for independent reproduction to facilitate the reproduction of the multicellular individual as a whole. Dissolution and death of multicellular individuals readily occurs when cooperation breaks down, cancer being a prime example. There are multiple mechanisms to ensure cooperation of component cells in most extant multicellular species. However, the origin and the maintenance of multicellularity are two distinct evolutionary problems. Component cells in a nascent multicellular organism would appear to have frequent opportunities to pursue individual non-cooperative reproductive strategies at a cost to the multicellular individual. How then does multicellularity evolve?
Multicellularity is studied in diverse model systems and by researchers in various fields. An understanding of the general principles involved in transitions from unicellular to multicellular life will benefit from integrating perspectives across these systems and fields of research. The purpose of this Catalysis meeting is to integrate the perspectives of scientists and scholars directly investigating multicellularity. The group will generate a foundational publication on the evolution and origins of multicellularity.